Traditional pesticides have disadvantage of tolerance problems when used a long time and somewhat harm to human. To overcome the drawbacks in the art, people have been developing new pesticides that are safer and more effective than those used in the art. It is the case that photosensitive compounds are developed as insecticides or fungicides.
Many photosensitive compounds exist in nature, but a great number of compounds that have photosensitive activity have been synthesized. Some of the compounds can generate active oxygen and a serial of free radicals under irradiation of light that harm organisms. Moreover, these compounds almost have no effect of toxicity to people. Therefore, people have paid much attention to the development of photosensitive compounds in the field of pesticides.
Chinese patents 96120600.4 and 96120599.7, of which the inventors of this application are co-inventors, disclose an insecticide composition comprising a natural perylenequinonoid, Hypocrellin A, and a method for preparing the same. However, perylenequinonoid derivatives (PQDs) as fungicides have not been disclosed in the art.